Are limited-slip and positraction the same thing?

In short: no. Positraction is a brand-name implementation of a limited-slip differential used by General Motors, while limited-slip differential (LSD) is the broader category that includes several different designs from multiple manufacturers.

What is a limited-slip differential?

A limited-slip differential is a type of drivetrain component that helps prevent one wheel from spinning freely when traction is uneven between wheels. Unlike an open differential, which splits torque equally and can send most power to the wheel with the least grip, an LSD limits the amount of slip, sending more torque to the wheel with better traction. This improves acceleration and cornering grip on slippery surfaces, wet roads, gravel, or snow. There are multiple design approaches within the LSD family, each with its own advantages and maintenance considerations.

There is a range of designs used in passenger cars and light trucks. The most common categories are described below:

• Clutch-type LSD: Uses friction plates and springs to create a preload that engages when one wheel starts to slip, transferring torque to the other wheel.


• Viscous LSD: Uses a viscous fluid or coupling that thins or thickens with shear between discs to transfer torque between wheels.


• Helical/Torsen (torque-sensing) LSD: Uses gears arranged to automatically bias torque to the wheel with more grip without electronic input.


• Electronic or control-based LSD: Combines sensors, actuators, or braking interventions to bias torque, sometimes in conjunction with mechanical clutches or torque-vectoring features.

The choice of LSD design affects how quickly it engages, how it behaves under cornering, and how predictable it is when you’re exiting a turn or accelerating on low-traction surfaces. Maintenance needs and wear characteristics also vary by design.

Positraction: a GM-brand take on the idea

Positraction is a heritage GM term for a specific type of limited-slip differential—traditionally a clutch-based design that preloads the differential to reduce wheel spin under traction loss. Introduced and marketed by General Motors, Positraction became a familiar feature on many GM cars and trucks for decades. While it represents a well-known implementation of an LSD, Positraction is not the only kind of LSD, and not every GM vehicle with an LSD uses the Positraction name today. Modern GM vehicles may use other LSD designs or electronically controlled traction systems, but the historical reference remains in automotive lore and some labeling (such as the old “Positraction” option badges or code names).

Positraction’s core idea—limit wheel slip by transferring torque to the wheel with more traction—still aligns with the broader LSD concept, but the exact mechanism, specifications, and performance can differ from other brands’ LSD solutions. If you’re shopping for a classic GM vehicle or restoring one, you’ll commonly encounter Positraction as a feature you can identify on brochures, VIN stubs, or service manuals, especially in older models.

Putting it all together: Are they the same?

The short, practical takeaway is that Positraction is a particular branded implementation of a limited-slip differential. LSD is the umbrella term for a family of devices designed to limit wheel spin and improve traction. Not all LSDs are Positraction, and not all cars labeled as Positraction use today’s newest LSD technology. For performance-minded buyers or restorers, the distinction matters when assessing maintenance needs, parts availability, and how the car will behave in low-traction conditions.

Summary

Limited-slip differentials cover several mechanical approaches to distributing torque to the wheel with better grip. Positraction is GM’s historic brand name for one such approach, typically a clutch-based LSD. While related, the terms are not interchangeable: Positraction represents a specific design and branding within the broader LSD category. Understanding the design in a given vehicle helps explain its traction behavior, maintenance requirements, and long-term reliability.

What is another name for limited slip differential?

positraction
Early in the development of limited-slip differential technology General Motors trademarked the term “positraction” (short for positive traction) for its limited-slip differential technology. Torsen, short for torque sensing, is another brand name associated with this technology.

How can I tell if my car has positraction?

Um or limited slip if it doesn't turn or it turns in the opposite. Direction then it means that you do not have limited slip. So let's give this a shot. So you can see my wheel is moving.

How do I tell if my differential is limited slip?

You can tell if your differential is a limited slip by performing a simple test on a lifted vehicle or by checking for a specific tag on the differential housing. With the rear wheels off the ground and the vehicle in neutral, spin one wheel by hand; if the other wheel spins in the same direction, it's a limited slip. If the other wheel spins in the opposite direction, it's an open differential. 
Method 1: Test the wheels

1. Park and secure the vehicle. Park on a level surface, engage the parking brake, and block the front wheels to prevent rolling. 
2. Safely lift the rear. Use a jack to lift the rear of the vehicle and secure it with jack stands. 
3. Place the transmission in neutral. Make sure the transmission is in neutral. 
4. Spin one rear wheel. Rotate one of the rear wheels by hand. 
5. Observe the other wheel. 
   • Same direction: If the opposite rear wheel turns in the same direction as the one you're spinning, you have a limited slip differential. 
   • Opposite direction: If the opposite rear wheel turns in the opposite direction, you have an open differential. 

This video demonstrates how to test if your car has a limited slip differential: 45sERICSDIYGARAGEYouTube · Dec 8, 2018
Method 2: Check the tag

1. Locate the differential. Find the differential housing at the rear of the vehicle. 
2. Look for a tag. Check for a sticker or tag on the differential that says, "Use only limited slip differential fluid". 
3. Consider the tag's reliability. This tag can sometimes be missing, damaged, or removed, so the wheel test is a more definitive method. 

This video shows how to check the tag on the differential housing: 51sChrisFixYouTube · Nov 26, 2012

Is posi the same as limited slip?

Posi-traction, also known as a limited slip differential (LSD), is a differential option that strikes a balance between an open and locking differential. Its purpose is to improve traction without sacrificing drivability.